This application claims benefit of priority under 35 USC 119 based on Japanese Patent Applications P2000-263619 filed Aug. 31, 2000, P2000-263621 filed Aug. 31, 2000 and P2000-263622 filed Aug. 31, 2000, the entire contents of which are incorporated by reference herein.
1. Field of the Invention
The present invention relates to a rotating and adjusting mechanism of a seat for a vehicle which supports a seat main body on a floor surface of a passenger""s room so as to freely rotate and adjust, and more particularly to an improvement of a rotating and adjusting mechanism of a seat for a vehicle which is provided with an annular lower base fixed to a floor surface side of a passenger""s room, an annular upper base to which a seat main body is adhered, and a holder adhered to an outer peripheral edge of the upper base and holding the lower base.
2. Description of the Related Art
In conventional, there has been known a rotary type vehicle seat employing a structure which can change and adjust an orientation of the seat in response to a passenger""s choice and desire.
That is, as this kind of rotary type vehicle seat, there has conventionally been proposed a mechanism in which a rotating and adjusting mechanism in accordance with a surface meeting system, a shaft-up rotary type or the like is provided below the seat main body by being interposed between the seat main body and the floor surface of the passenger""s room.
In Japanese Patent Application Laid-Open No. 8-11600, the structure is provided with an annular lower rail fixed to a floor side of the vehicle, an upper rail having a substantially U-shaped sliding portion slidably engaging with an annular sliding portion having a substantially inverted-U cross sectional shape of the lower rail, and a bracket for fixing the upper rail to a seat cushion frame. There is shown a seat rotating apparatus in which a ball is interposed between the annular sliding portion of the lower rail and the bracket, and an outer wall surface of the annular sliding surface with which the ball is in contact is formed in a taper surface moving to an inner downward direction, thereby achieving an automatic aligning function.
Further, in Japanese Patent Application Laid-Open No. 11-129794, there has been shown a structure having a lower plate provided in a floor side, an upper plate provided in a side of a seat and supported to the lower plate via a ball so as to rotate on its axis on a horizontal surface, and a set plate connected to the lower plate by a caulking pin and gripping the upper plate together with the lower plate via the ball. Further, the structure is made so as to adjust and change an opposing interval between the set plate and the lower plate by collapsing a boss portion of the set plate, so that it makes a rotating torque of the upper plate proper.
As shown in FIG. 1, a lock mechanism 101 is provided in a rotating and adjusting mechanism 100 of a seat. The lock mechanism 101 is structured such that a lock hole 121 is provided in a lower base 11 and a lock hook 125 of a rotary lever 123 pivoted to a side of an upper base is inserted to and engaged with the lock hole 121, whereby the rotating and adjusting mechanism 100 of the seat can be made in a lock state.
However, in the seat rotating apparatus shown in Japanese Patent Application Laid-Open No. 8-11600, the lower rail is opposed to the upper rail having the substantially U-shaped sliding portion slidably engaged with the substantially U-shaped annular sliding portion of the lower rail via a shoe. Accordingly, a sliding resistance is increased and a sufficient aligning function cannot be obtained, so that there is a risk that a dispersion is generated. Further, there are disadvantages that the bracket and the upper rail are easy to be deformed when an impact load from the seat side is applied to the bracket and the upper rail, a weight is increased since it is impossible to reduce a thickness, and it is impossible to perform a simple and rapid rotating operation due to an increase of the sliding resistance. In the case that the ball between the bracket and the lower rail is positioned above the taper surface, the bracket is positioned at a high position in a vertical direction. The position of the bolt by which the bracket is adhered to the upper rail becomes high, so that there is a disadvantage that the height of the seat mounting surface becomes high.
In the rotating apparatus shown in Japanese Patent Application Laid-Open No. 11-129794, it is possible to reduce a height in a vertical direction of a lower plate, however, the lower plate becomes longer in a horizontal direction, so that it is impossible to make the structure of the rotating apparatus compact. Accordingly, there are disadvantages that the weight of the rotating apparatus is increased and the sliding resistance is increased.
An object of the present invention is to provide a rotating and adjusting mechanism of a seat for a vehicle satisfied with below effects:
(1) The rotating and adjusting mechanism of a seat for a vehicle comprising a lower base, an upper base and a holder can be simply structured by a minimum number of parts.
(2) An automatic aligning function can be provided in the rotating and adjusting mechanism of a seat for a vehicle.
(3) An impact load can be securely transmitted from the holder to the lower member.
(4) A thickness of the seat can be reduced due to a less deformation of the seat.
(5) A sliding resistance can be reduced by lessening a weight of the seat.
(6) The rotational adjustment of the seat can be easily and rapidly performed by reducing a rotational operating force.
(7) The seat can be made compact by reducing a height thereof.
(8) Adhering members such as a bolt and the like do not protrude upward at a mounting position of the upper base and the holder.
(9) A seat mounting surface can be made flat.
(10) Rigidity of the seat in a vertical direction can be improved.
(11) The play of the seat is not generated.
(12) The cost of the seat becomes inexpensive.
The first aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle, comprising: an annular lower base fixed to a floor surface side of a passenger""s room; an annular upper base to which a seat main body is adhered; and a holder adhered to an outer peripheral edge of the upper base, and gripping the lower base, wherein an engaging and sliding portion having a substantially inverted-U cross sectional shape is formed in the annular lower base, the upper base is arranged via the engaging and sliding portion of the lower base and a first rolling member, a sliding portion having a substantially U cross sectional shape, which is engaged with the substantially inverted-U shaped engaging and sliding portion in the lower base, is formed in the holder, a second rolling member is provided between the sliding portion of the holder and the engaging and sliding portion of the lower base, and the first rolling member and the second rolling member are arranged so that a line connecting a center of the first rolling member and a center of the second rolling member is inclined.
The second aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the first aspect of the invention, wherein a recess receiving a lower end of the first rolling member and a convex portion receiving the second rolling member, are formed in an upper end of the substantially U cross sectional shaped engaging and sliding portion of the lower base, and wherein a substantially S-shaped receiving portion is formed by the recess and the convex portion.
The third aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the first aspect of the invention, wherein a linear portion is formed in a receiving portion receiving an upper end of the first rolling member of the upper base.
The fourth aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the first aspect of the invention, wherein a recess is formed at a position of an adhered portion of the holder in the upper base, and an adhered portion of the seat main body in the upper base, is formed in substantially linear shape.
The fifth aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the first aspect of the invention, wherein a mounting portion having a substantially inverted-U cross sectional shape is formed in the holder.
The sixth aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the fifth aspect of the invention, wherein the substantially inverted-U cross sectional shaped mounting portion is formed in the holder so as to be continuously connected to the substantially U cross sectional shaped sliding portion.
The seventh aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the first aspect of the invention, wherein a plurality of lock holes are pierced in the engaging and sliding portion of the lower base, a rotating lever having lock hooks inserted to the lock holes in the lower base is pivoted to the upper base, and a lever guide for guiding the lock hooks in the rotating lever is formed in the upper base.
The eighth aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the seventh aspect of the invention, wherein the lever guide for guiding a lower surface side of the lock hooks in the rotating lever is provided in the holder in a side opposing to the lever guide of the upper base.
The ninth aspect of the invention provides a rotating and adjusting mechanism of a seat for a vehicle according to the seventh aspect of the invention, wherein a pivotal point of the rotating lever with respect to the upper base, is formed in a connecting direction of the lock holes in the lower base corresponding to a direction perpendicular to an inserting direction of the lock hook.